Effect of Cholic Acid on Fetal Cardiac Myocytes in Intrahepatic Choliestasis of Pregnancy

This study examined the effect of cholic acid （CA） on cultured cardiac myoeytes （CMs） from neonatal rats with an attempt to explore the possible mechanism of sudden fetal death in intra- hepatic cholestasis of pregnancy （ICP）. Inverted microscopy was performed to detect the impact of CA on the beating rates of rat CMs. MTT method was used to study the effect of CA on the viability of CMs. CMs cultured in vitro were incubated with 10 ~maol/L Ca2＋-sensitive fluorescence indicator fluo-3/AM. The fluorescence signals of free calcium induced by CA were measured under a laser scanning confocal microscope. The results showed that CA decreased the beating rates of the CMs in a dose-dependent manner. CA could suppress the activities of CMs in a time- and dose-dependent manner. CA increased the concentration of intracellular free calcium in a dose-dependent manner. Our study suggested that CA could inhibit the activity of CMs by causing calcium overload, thereby leading to the sudden fetal death in ICP.

In Vitro Study on Mesenchymal Stem Cells:Anti-apoptotic Effects on Cardiac Myocytes

Objectives To investigate the anti-apoptotic effects of mesenchymal stem cells （MSCs） on hypoxic injured cardiac myocytes in vitro. Methods MSCs were isolated from bone marrow of Sprague-Dawley （SD） rats, and cardiac myocytes from neonatal rats. The rat cardiac myocytes were co-cultured with MSCs or MSC-conditioned media in anoxia （95% N2 ±5% CO2） for 72 hours. Cell apoptosis was measured by Hoechst 33258 staining. The expression of Bcl-2 and Bax in cardiac myocytes was tested by Western Blot. Results The apoptotic rate was 51.6% ± 2.4% when cardiac myocytes were cultured in continuous hypoxia and was significantly decreased when cardiac myocytes were cocultured with MSCs or MSC-conditioned media （ 15.1% ± 5.4% and 24. 0% ± 4.2% respectively, P 〈 0. 001 ）. The decreased expression of Bax in the cardiac myocytes was greatly related to the decreasing of apoptosis, but there was no difference in Bcl-2 expression among these groups. Conclusions Co-cultured MSCs showed significant anti-apoptotic effects on cardiac myocytes in continuous hypoxia. The mechanism may be the interact of cell to cell and paracrine of cytokines which effected the expression of Bax in the cardiac myocytes.

Antioxidant Effect of Human Selenium-containing Single-chain Fv in Rat Cardiac Myocytes

Reactive oxygen species（ROS） plays a key role in human heart diseases. Glutathione peroxidase（GPX） functions as an antioxidant as it catalyzes the reduction of hydroperoxide. In order to investigate the antioxidant effect of human selenium-containing single-chain Fv（Se-scFv-B3）, a new mimic of GPX, a model system of hydrogen peroxide（H202）-induced rat cardiac myocyte damage was established. The cardiac myocyte damage was characte- rized in terms of cell viability, lipid peroxidation, cell membrane integrity, and intracellular H202 level. The Se-scFv-B3 significantly reduced H2O2-induced cell damage as shown by the increase of cell viability, the decline of malondialdehyde（MDA） production, lactate dehydrogenase（LDH） release, and intracellular H2O2 level. So Se-scFv-B3 may have a great potential in the treatment of human heart diseases induced by ROS.

Effects of adiponectin on oxidative stress and apoptosis in human cardiac myocytes cultured with high glucose

Background Diabetic cardiomyopathy is the major cause of morbidity and mortality in diabetic patients. Oxidative stress plays an important role in diabetic cardiomyopathy. This study aimed to investigate the effects of adiponectin on oxidative stress and apoptosis in human cardiac myocytes （HCM） cultured with high glucose. Methods The cells were assigned to three group： control group, high glucose group and high glucose plus adiponectin group. After culture for 24, 48, 72 hours, oxidative stress was evaluated by detecting levels of malondialdehyde （MDA） and superoxide dismutase （SOD） in the supernatant of culture media. The expression of p66Shc and Heme oxygenase-1 （HO-1） was detected by real-time polymerase chain reaction （PCR）. Flow cytometry was designed to observe and detect cellular apoptosis. Results Our findings showed significant increase in MDA levels and decrease in SOD activity in the high glucose group compared with the control group （P 〈0.05）. However, MDA levels were significantly decreased and SOD activity was significantly increased in the adiponectin group compared with those in the high-glucose group （P 〈0.05）. The mRNA expression of HO-1 in the high glucose group was significantly increased in a time-dependent manner compared with that in the control group （P 〈0.05）. Adiponectin further increased the mRNA expression of HO-1 induced by high glucose in a time-dependent manner （P 〈0.05）.The expression of p66Shc was significantly increased in high glucose group compared with that in the control group （P 〈0.05）. Adiponectin significantly suppressed the upregulation of p66Shc induced by high glucose （P 〈0.05）. The apoptotic rate of cardiomyocytes was significantly increased in the high glucose group compared with that in the control group while the apoptotic rate in the adiponectin group was remarkably declined in comparison with that in the high glucose group. Conclusion Adiponectin reduces high glucose-induced oxidative stress and apoptosis and plays a protective role in myocardial cells by upregulating the HO-1 expression and downregulating p66Shc expression.

Ultrasonic destruction of albumin microbubbles enhances gene transfection and expression in cardiac myocytes

Background It has been proven that ultrasonic destruction of microbubbles can enhance gene transfection efficiency into the noncardiac cells, but there are few reports about cardiac myocytes. Moreover, the exact mechanisms are not yet clear; whether the characteristic of microbubbles can affect the gene transfection efficiency or not is still controversial.This study was designed to investigate whether the ultrasound destruction of gene-loaded microbubbles could enhance the plasmids carried reporter gene transfection in primary cultured myocardial cell, and evaluate the effects of microbubbles characteristics on the transgene expression in cardiac myocytes.Methods The β-galactosidase plasmids attached to the two types of microbubbles, air-contained sonicated dextrose albumin （ASDA） and perfluoropropane-exposed sonicated dextrose albumin （PESDA） were prepared. The gene transfection into cardiac myocytes was performed in vitro by naked plasmids, ultrasound exposure, ultrasonic destruction of gene-loaded microbubbles and calcium phosphate precipitation, and then the gene expression and cell viability were analyzed.Results The ultrasonic destruction of gene-loaded microbubbles enhanced gene expression in cardiac myocytes compared with naked plasmid transfection （（51.95±2..41） U/g or （29.28±3.65） U/g vs. （0.84-0.21） U/g, P ＜0.01）, and ultrasonic destruction PESDA resulted in more significant gene expression than ASDA （（51.95e2.41） U/g vs. （29.28±3.65）U/g, P ＜0.05）. Ultrasonic destruction of microbubbles during calcium phosphate precipitation gene transfection enhanced 3-galactosidase activity nearly 8-fold compared with calcium phosphate precipitation gene transfection alone （（111.35±11.21） U/g protein vs. （14.13±2.58） U/g protein, P＜0.01）. Even 6 hours after calcium phosphate precipitation gene transfection, ultrasound-mediated microbubbles destruction resulted in more intense gene expression （（35.63±7.65）U/g vs. （14.13±2.58） U/g, P＜0.05 ）.Conclusions Ultrasonic destruction of microbubbles might be a promising method for the delivery of non-viral DNA into cardiac myocytes, and the gene tranfection is related to the characteristics of microbubbles.

Effects of hypoxia on promoter of telomerase reverse transcriptase and cell cycle distribution in neonatal rat cardiac myocytes

On the hypothesis that telomerase reverse transcriptase (TERT) of cardiac myocytes (CMs) is consistent with cell cycle distribution as well as tumour cells, we plan to investigate the expression of TERT in CMs and how TERT is in keeping with CMs cycle distribution after birth and under hypoxia, and roughly understand how hypoxia affects activity of TERT promoter.

Epidermal gowth factor receptor participates in growth hormone signaling pathway in cardiac myocytes of neonatal rat

Objective To examine whether growth hormone (GH) promotes the phosphorylation of epidermal growth factor (EGF) receptor and to elucidate the mechanisms by which EGF receptors were transactivated by GH stimulation Methods Cultured cardiac myocytes were stimulated by GH directly or pretreated with inhibitors before GH stimulation The phosphorylations of EGF receptor and JAK 2 were examined with immunoprecipitation followed by Western blotting using anti phosphotyrosine antibody (4G10) The activities of extracellular signal regulated kinases (ERKs) were assayed with the method of MBP containing gel Results GH stimulated phosphorylation of EGF receptor in a time dependent manner Tyrphostin AG1478, a selective inhibitor of EGF receptor, strongly suppressed GH induced ERK activation, while tyrphostin AG1295, a selective inhibitor of PDGF receptor, had no effects on the activation of ERKs stimulated by GH in cardiac myocytes In addition, GH induced tyrosine phosphorylation of JAK 2, a cytoplasmic protein tyrosine kinase, in cardiac myocytes Moreover, tyrphostin B 42 , an inhibitor of JAK 2 suppressed GH induced phosphorylation of EGF receptor as well as GH induced activation of ERKs in cardiac myocytes Conclusions GH evokes the phosphorylation of EGF receptor in cardiac myocytes through activating JAK 2 Phosphorylated EGF receptor plays a critical role in GH signaling pathway leading to ERK activation in cardiac myocytes

Frequency of apoptosisin cardiac myocytes of patients with myocarditisand dilated cardiomyopathy

Background Programmed cell death has previously been observed in animal models of viral myocarditis and in patients with end stage dilated cardio myopathy (DCM). The purpose of the present study was to investigate if apoptosis is also detectable in endomyocardial biopsies of patients with clinical and immuno histological signs of myocarditis. Methods Right ventricular myocardial biopsies were obtained from 53 patients with clinically suspected myocarditis (left ventricular ejection fraction 30±14%). Cardiac tissues from 4 patients with end stage heart failure were obtained during heart transplantation. Diagnosis of myocarditis and DCM was based on clinical presentation and on histological and immunohistological findings. The presence of apoptosis was investigated in paraffin embedded tissue sections by in situ end labeling of nuclear DNA strand breaks. Results By histological and immunohistological analysis 19 patients (36%) were diagnosed as myocarditis and 34 patients (64%) as DCM. Apoptosis was detected in 9 out of 19 patients with myocarditis, in 12 out of 34 patients with DCM (47% versus 35%, p=NS), and in all patients with end stage heart failure. Conclusions A high frequency of apoptosis was detectable in endomyocardial biopsies of patients with immunohistologically documented myocarditis. The rate of apoptosis in patients with myocarditis, however, was not different to patients with DCM. These findings suggest that apoptosis may be one common pathway in the pathogenesis of cardiac contractile dysfunction in patients with myocarditis and DCM.

Gene Product Expression of Cyclin D_2 and p16 During the Transition from Cardiac Myocyte Hyperplasia to Hypertrophy

The current study was to investigate mRNA expression of cyclin D 2 and p16 during the transition from cardiac myocyte hyperplasia to hypertrophy. Cultured cardiac myocytes (CM) and fibroblasts (FC) obtained from 1 day old Sparague Dawley rats were used in this study. We have determined (1) hyperplasia by cell growth curve and fluorescence activated cell sorting (FACS); and (2) ultrastructure by electron microscope observation; and (3) expressions of cyclin D 2 mRNA and p16 mRNA by using in situ hybridization and image analysis. The results were shown (1) Results of cell growth curve and FACS analysis showed CM could proliferate in the first 3 cultured days (4 days in postnatal development). But the ability decreased quickly, concomitant with the differentiation. (2) The ultrastructure of CM showed the large amount of myofilaments and mitochondrion and FC showed moderate amount of rough endoplasmic reticulum. (3) The expression of cyclin D 2 mRNA in 3 , 4 , 5 day CM group was 0.89 times(p<0.05), 0.80 times (p<0.05)and 0.56 times (p<0.01)of that in 1 day group respectively. P16 mRNA in 2 , 3 , 4 , 5 day CM group were 1.63 times(p<0.01),1.72 times(p<0.01),1.99 times (p<0.01)and 2.84 times (p<0.01) of that in 1 day group respectively. It can be concluded that cultured neonatal rat cardiac myocytes could proliferate during the first 3 cultured days, but the ability of proliferation decreased, from the fourth day, concomitant with differentiation. Cyclin D 2 and p16 have the key roles during the transition from myocyte hyperplasia to hypertrophy.

Regulations of Thyroid Hormone on Cardiac Protein Kinase C Signal Pathway in vitro

The experiments were conducted to assess the influences of thyroid hormone on cardiac protein kinase C(PKC) signal pathway with cultured cardiac myocytes and fibroblasts as the models. Cells were pretreated with 1% newborn calf serum (NCS) or angiotensin II (Ang II), and then following by a triiodothyronine (T3) treatment. The PKC activity, PKCα and PKCε expressions were analyzed and compared. In 1% NCS pretreatment, T3 could inhibit PKC activity and PKCε expression in cardiac myocytes. The AngII pretreatment led to an increase of PKC activity and PKCε expression in cardiac myocytes, and an increase of PKC activity in cardiac fibroblasts. Following by T3 treatment, the increased PKC activity and PKCε expression in cardiac myocytes were markedly decreased. In conclusion, whether in 1% NCS or in Ang II pretreatment, T3 could inhibit PKC activity and PKCε expression in cardiac myocytes. Key words thyroid hormone - cardiac myocytes - cardiac fibroblasts - protein kinase C CLC number Q 572 Foundation item: Supported by the Natural Science Foundation of Hubei Province (98091)Biography: WANG Bao-hua (1974-), female, Ph. D, research direction: cardiovascular pathophysiology.

STUDY ON MECHANICAL INTERACTIONS BETWEEN SINGLE CARDIAC MYOCYTE AND ELASTIC SUBSTRATE

Quantitative investigation on mechanical characteristics of cardiac myocytes has important physiological significance. Based on elastic substrate technique, this paper develops a set of algorithms for high-efficiency cellular traction recovery. By applying a gradient-based digital image correlation method to track randomly distributed fluorescence microbeads on the deformed substrate induced by single cardiac myocyte, high-resolution substrate displacement field can readily be obtained. By using a numerical algorithm based on the integral Boussinesq solution, cell-substrate tractions are reconstructed in a stable and reliable manner. Finally, spatiotemporal dynamics of a single cardiac myocyte is investigated as it adheres to a polyacrylamide elastic substrate.

Antioxidant Effect of Selenium-containing Glutathione S-Transferase in Rat Cardiomyocytes

As one of the most important antioxidant enzymes, glutathione peroxidase（GPX） protects cells and tissues from oxidative damage, and plays an important role in cardiovascular and cerebrovascular injuries induced by oxida- tive stress. The antioxidant effect of selenium-containing glutathione S-transferase（Se-GST）, a mimic of GPX was investigated on rat cardiomyocytes. To explore the protection function of Se-GST in hydrogen peroxide（H202） chal- lenged rat cardiomyocytes, we examined malondialdehyde（MDA）, lactate dehydrogenase（LDH）, superoxide dismu- tase（SOD） and cell apoptosis. The results demonstrate exposure of rat cardiomyocytes to H202 for 6 and 12 h induced the significant increases of MDA, LDH and apoptosis rate of cardiomyocytes, but pretreatment of rat cardiomyocytes with Se-GST at 0.0005 or 0.001 unit/mL prevents oxidative stress induced by H202 with the decreases of cell apopto- sis. All the results hint Se-GST has antioxidant activity for oxidative stress challenged rat cardiomyocvtes.

GRK5 is an essential co-repressor of the cardiac mineralocorticoid receptor and is selectively induced by finerenone

BACKGROUND In the heart,aldosterone(Aldo)binds the mineralocorticoid receptor(MR)to exert damaging,adverse remodeling-promoting effects.We recently showed that G protein-coupled receptor-kinase(GRK)-5 blocks the cardiac MR by directly phosphorylating it,thereby repressing its transcriptional activity.MR antagonist(MRA)drugs block the cardiac MR reducing morbidity and mortality of advanced human heart failure.Non-steroidal MRAs,such as finerenone,may provide better cardio-protection against Aldo than classic,steroidal MRAs,like spironolactone and eplerenone.AIM To investigate potential differences between finerenone and eplerenone at engaging GRK5-dependent cardiac MR phosphorylation and subsequent blockade.METHODS We used H9c2 cardiomyocytes,which endogenously express the MR and GRK5.RESULTS GRK5 phosphorylates the MR in H9c2 cardiomyocytes in response to finerenone but not to eplerenone.Unlike eplerenone,finerenone alone potently and efficiently suppresses cardiac MR transcriptional activity,thus displaying inverse agonism.GRK5 is necessary for finerenone’s inverse agonism,since GRK5 genetic deletion renders finerenone incapable of blocking cardiac MR transcriptional activity.Eplerenone alone does not fully suppress cardiac MR basal activity regardless of GRK5 expression levels.Finally,GRK5 is necessary for the antiapoptotic,anti-oxidative,and anti-fibrotic effects of both finerenone and eplerenone against Aldo,as well as for the higher efficacy and potency of finerenone at blocking Aldo-induced apoptosis,oxidative stress,and fibrosis.CONCLUSION Finerenone,but not eplerenone,induces GRK5-dependent cardiac MR inhibition,which underlies,at least in part,its higher potency and efficacy,compared to eplerenone,as an MRA in the heart.GRK5 acts as a co-repressor of the cardiac MR and is essential for efficient MR antagonism in the myocardium.

FINITE ELEMENT ANALYSIS OF CARDIAC MYOCYTE DEBONDING AND REORIENTATION DURING CYCLIC SUBSTRATE STRETCH EXPERIMENTS

The substrate stretch experiment, which is carried out on several kinds of adherent cells, is usually used to catch the physiological variation and morphological response to cyclic substrate deformation. In this paper, stretch loading was exerted on cardiac myocytes cultured on silica substrates using a custom-made substrate stretch device. The effect of stretch on the alignment orientation of cardiac myocytes was studied through morphocytological statistics. Under cyclic stretch stimulus, the long axes of cardiac myocytes oriented perpendicularly to the stretch direction for continuous stretch acting. However, the mechanism underlying these behaviors is not well understood from such in vitro tests. Finite element （FE） model was developed in the analysis to investigate these behaviors. Xu-Needleman formulation was used to define the interaction behavior for contact surfaces between cell and substrate. The role of cell viscoelasticity nature is studied in adherent cell debonding with the substrate and aligning perpendicular to the stretch direction during long time cyclic stretch stimulation. There were four different strain magnitudes considered in the simulation to find out the cell debonding affected by the cyclic strains. The potential role of cyclic strain frequency in regulating cell debonding and alignment was also studied using FE analysis.

The Study on Intramyocardial Calcium Overload and Apoptosis Induced by Cosackievirus B3

The isolated cardiac myocytes of rats were immediately infected by cosackievirus B3 (CVB3) to investigate the effects of such procedure on the cell cycle, apoptosis and intracellular ionized calcium (Ca 2+ i) of cardiac myocytes. Newborn Balb/c murine cardiac myocytes were cultivated, then infected by CVB3. Intracellular Ca 2+ i was measured by flow cytometer. The calcium in the medium for culturing cardiac myocytes was detected by using atom absorb spectrum test. It was found that CVB3 could markedly inhibit the differentiation and proliferation of the infected cardiac myocytes and induce the apoptosis. The intracellular Ca 2+ i level in the infected group was significantly higher than in the control group (P<0.01). The calcium concentration in the medium for culturing cardiac myocytes in the infected group was significantly lower than in the control group (P<0.05). It was suggested that the apoptosis and intracellular calcium overload of the CVB3-affected cardiac myocytes are likely to play an important role in the pathogenesis of viral myocarditis.

Effect of allitridi on calcium current in rat ventricular myocytes

Background Allitridi is an active compound that is extracted from the garlic. It has effects of anti-atherosclerosis, anti-arrhythmias and lowering blood pressure. But the controversy about the effect on cardiac contractility still exists. Methods Whole-cell patch clamp recording technique was used to record ICa,Lin single cell isolated rat ventricular myocytes. The nifedipine- sensitive L-type calcium current was recorded in the rat ventricular myocytes. Results Allitridi decreased the calcium channel current in a dose-dependent and voltage-dependent manner in ventricular myocytes of rats. The current-voltage curve was shifted upwards, on which active potential,peak potential and reverse potential showed no significant changes. The inactivation curve was shifted to more negative potential, but the activation curve and recovery curve were not altered. Allitridi had no effect on frequent-dependency of calcium current. Conclusion These results show that allitridi could concentration-dependently decrease calcium channel current in ventricular myocytes of rats.

Effect of Sodium Tanshinone ⅡA Sulfonate on Cardiac Myocyte Hypertrophy and Its Underlying Mechanism

Objective： To investigate the effects of sodium tanshinone Ⅱ A sulfonate （STS） on the hypertrophy induced by angiotensin Ⅱ（Ang Ⅱ） in primary cultured neonatal rat cardiac myocytes. Methods： The effect of STS on cytotoxicity was evaluated using the 3-（4,5-dimethylthiazol-2-yl）-3,5- phenytetrazoliumromide （MTT） assay. As indexes for cardiocyte hypertrophy, cell size was determined by phase contrast microscopy and protein synthesis rate was measured by 3H-leucine incorporation. The proto-oncogene c-fos mRNA expression of cardiocytes was assessed using reverse transcription polymerase chain reaction （RT-PCR）. Results： STS could inhibit cardiocyte hypertrophy, increase the protein synthesis rate and enhance proto-oncogene c-fos mRNA expression in cardiocytes induced by Ang Ⅱ（P〈0.01）, with an effect similar to that of Valsartan, the Ang Ⅱ receptor antagonist. Conclusion： STS can prevent the hypertrophy of cardiac myocytes induced by Ang Ⅱ, which may be related to its inhibition of the expression of proto-oncogene c-fos mRNA.

Transplantation of neonatal cardiomyocytes plus fibrin sealant restores myocardial function in a rat model of myocardial infarction

Background Most cardiac regenerative approaches can restore injured heart muscles. In this study, we investigated if fibrin sealant could help neonatal cardiomyocytes restore myocardial function in a rat model of myocardial infarction. Methods The left anterior descending artery in adult female Sprague-Dawley （SD） rats was ligated to make a myocardial infarction model. Neonatal ventricular cardiomyocytes from one-day male SD rats were isolated, labeled and cultured. The cells were injected into the infarcted area three weeks later. The animals were randomized into four recipient groups： （1） cardiomyocytes plus fibrin sealant （group CF, n=10）; （2） cardiomyocytes alone （group C, n=10）; （3） fibrin sealant recipients alone （group F, n=10）; （4） control group （n=10）. Four weeks after transplantation, echocardiography and Langerdoff model were used to assess heart function. Immunohistochemical staining and polymerase chain reaction （PCR） were performed to track the implanted cardiomyocytes and detect the sex-determining region Y gene on Y chromosome. Results Echocardiography showed the fraction shortening （FS） in groups CF, C, F and control group was （27.80±6.32）%, （22.29±4.54）%, （19.24±6.29）% and （20.36±3.29）% respectively with statistically significant differences in group CF compared with the other groups （P〈0.05）. The Langendoff model revealed that the left ventricular development of peak pressure （LVDPmax, mmHg） in groups CF, C, F and control group was 104.81±17.05, 80.97±21.60, 72.07±26.17 and 71.42±17.55 respectively with statistically significant differences in group CF compared with the other groups （P〈0.05）. Pathological examination and PCR indicated that transplanted cardiomyocytes in group CF survived better than those in the other groups. Conclusion Transplanted neonatal cardiomyocytes plus fibrin sealant can survive in myocardial infarctioned area and improve heart function greatly in rat models.

Efficacy of water fraction from Dioscorea cirrhosa on oxidative stress and apoptosis in H9c2 cardiomyocytes induced by H2O2

OBJECTIVE:To investigate the efficacy of water fraction from Dioscorea cirrhosa(WF)on oxidative damage and apoptosis of cardiomyocytes induced by H2O2,and to study its mechanism.METHODS:Cell viability was measured by the MST assay kit.The content of malondialdehyde(MDA),release of lactate dehydrogenase(LDH)and activity of catalase(CAT)and superoxide dismutase(SOD)were detected by biochemical kit.The content of reactive oxygen species(ROS)was assessed by nonfluorescent probe 2′,7′-dichlorofluorescin diacetate(DCFH-DA).JC-1 was used to analyze the mitochondrial membrane potential(mtΔΨ)and Annexin-V-FITC/PI staining was applied to assess apoptosis of H9c2 by flow cytometry.Moreover,the expression of B-cell lymphoma-2(Bcl-2),Bcl-2-associated X(Bax),caspase-3,caspase-9,cleaved-caspase-3 and cleaved-caspase-9 proteins was determined by western blot analysis.RESULTS:WF increased cell viability and decreased LDH leakage in H9c2 cells exposed to H2O2.WF treatment decreased ROS and MDA level,enhanced SOD and CAT activities,improved mtΔΨand inhibited apoptosis.Western blot analysis demonstrated that the ratio of Bcl-2/Bax was increased and the expression cleaved-caspase-3,caspase-3,cleaved-caspase-9 and caspase-9 were decreased in group treated with WF.CONCLUSION:WF protects H9c2 myocardial cells on H2O2-induced oxidative stress and apoptosis by scavenging ROS,improving antioxidant capacity,protecting mitochondrial and regulating the proteins expression related to apoptosis.

Current state of myocardial tissue engineering

Ischemic heart disease and dilated cardiomyopathy followed by heart failure are a worldwide problem,which seriously challenge clinical outcomes and quality of life of patients. Heart failure is one of the major causes of morbility and mortality. The human heart cannot regenerate significantly because adult cardiomyocytes are terminally differentiated and cannot replicate after injury. The loss of cardiomyocytes accounts for a decrease in myocardial function, which leads to heart failure. Conservative treatment for cardiac conditions has focused on the reduction of workload, and protection from risk factors and has little therapeutic effect on patients in end-stage heart failure. Heart transplantation represents a life-saving and life-extending treatment modality for end-stage heart failure. In spite of advances in surgical techniques, the shortage of availability of donor organs has limited this treatment modality and has prompted researchers to develop alternative approaches. Cardiomyocyte regeneration is a prospective treatment modality, of which, in vitro engineering of myocardial tissue has had promising outcomes that should help cope with failing hearts in the future. Over the past years, much progress has been made to replace infarcted, non-functioning myocardium with newly formed tissue by means of cell-grafting techniques. Our country has made substantial progress in this field and promises a bright future for clinical management of heart failure.